You lean down to check on your pup, and a strong odor hits your nose—followed by another troubling sign: they’re refusing to eat.
Bad breath alone is often brushed off as “normal dog smell,” but when it shows up alongside appetite loss, it becomes a warning that something deeper may be wrong.
We help you understand why these symptoms may appear together, what underlying conditions could be at play, what you can do at home, and when to visit your veterinarian.
Dog Bad Breath and Not Eating: Why It Happens
A dog with bad breath and not eating may be dealing with dental disease, oral infections, kidney disease, diabetes, gastrointestinal problems, tumors in the mouth, or something as serious as liver failure.
These conditions not only affect how their breath smells but also lead to discomfort, nausea, or pain that suppresses appetite.
Dog Bad Breath and Not Eating: Common Causes
1. Dental Disease
Dental problems are one of the most common reasons a dog has bad breath and doesn’t want to eat. Over time, plaque and tartar build-up on your dog’s teeth and along the gumline. This creates a perfect environment for bacterial infections, leading to gingivitis, loose teeth, and even abscesses.
As the infection worsens:
The breath becomes foul, often described as “rotten” or metallic
Eating becomes painful, especially if chewing causes sharp discomfort
Your dog may drool, chew only on one side, or drop food from their mouth
Dogs may still approach their bowl out of habit, then walk away without eating. In severe cases, they may paw at their mouth, refuse hard food, or become lethargic.
Related: Dog vomiting and not eating (Causes and when to worry)
2. Oral Masses or Tumors
A less common but serious cause of bad breath and appetite loss is oral tumors. Cancerous growths in the mouth, tongue, or throat can become infected, bleed, or interfere with chewing and swallowing. Dogs with oral tumors often display:
A persistent foul odor (even after brushing or dental cleanings)
Visible lumps in or around the mouth
Blood in saliva or food bowl
Avoidance of eating or sudden food pickiness
These symptoms warrant immediate veterinary evaluation, especially in older dogs or breeds prone to oral cancer (like Boxers, Golden Retrievers, or Cocker Spaniels).
3. Kidney Disease
Bad breath with a chemical or ammonia-like odor is often a red flag for kidney disease. When the kidneys aren’t filtering waste properly, toxins accumulate in the bloodstream. This uremia leads to:
Nausea and vomiting
A metallic or “urine-like” breath odor
Fatigue and disinterest in food
Dehydration and weight loss
This condition is more common in older dogs, but can occur in any age group, especially with toxin exposure. If your dog’s breath smells unusually sharp or foul and they’ve stopped eating, kidney disease must be ruled out.
4. Gastrointestinal Disorders
Sometimes, bad breath comes from the gut, not the mouth. A dog with chronic GI issues may have bad breath due to acid reflux, bacterial imbalance, or slow digestion. These problems often come with:
Gurgling stomach noises
Vomiting or regurgitation
Grass-eating behavior
Drooling or lip-smacking
Disinterest in food, especially dry kibble
Digestive issues cause discomfort that suppresses appetite and alter the balance of bacteria in the mouth and gut, creating unusual smells. Inflammatory bowel disease (IBD), ulcers, or even parasites can be behind the symptoms.
5. Diabetes
Dogs with untreated or uncontrolled diabetes often develop sweet or fruity-smelling breath, a result of ketone production. Alongside this, they may lose interest in food due to nausea caused by blood sugar fluctuations or diabetic ketoacidosis (a medical emergency).
Common symptoms include:
Lethargy or confusion
Increased thirst and urination
Weight loss despite eating
Vomiting or food refusal
If your dog has bad breath and stops eating and drinking, especially with changes in thirst or urination, diabetes or diabetic complications may be the cause.
6. Liver Disease
Liver dysfunction can lead to a condition called hepatic encephalopathy, where toxins bypass the liver and affect the brain and body. This may cause:
Musty, sweet-smelling breath
Loss of appetite
Behavioral changes (confusion, pacing)
Jaundice (yellowing of eyes or gums)
Dogs with liver issues often stop eating due to nausea and systemic discomfort. If your dog’s bad breath is accompanied by disorientation, vomiting, or lethargy, seek vet care quickly.
What to Do If Your Dog Has Bad Breath and Isn’t Eating
If your dog refuses food and has persistent bad breath, start with these at-home steps (if they’re otherwise stable):
Examine their mouth (gently) for redness, swelling, or visible sores
Offer soft or bland food (boiled chicken, rice) that’s easier to chew
Try warming wet food to enhance smell and appeal
Add broth or water to food to reduce chewing effort
Ensure access to clean water and encourage drinking
Avoid brushing their teeth or forcing the mouth open if they appear in pain. If your dog hasn’t eaten in 24 hours or seems unwell, contact your vet right away.
When to Call or Visit Your Vet
Get veterinary attention if your dog:
Has not eaten for 24 hours or longer
Shows pain when eating, chewing oddly, or pawing at the mouth
Has breath that smells like ammonia, metal, or rotting tissue
Is drooling excessively, vomiting, or acting lethargic
Has visible mouth sores, bleeding gums, or tooth loss
Is older or has a known chronic health condition
Your vet may perform a full oral exam, dental X-rays, blood tests, or imaging to identify the issue. Early intervention is key—especially in senior dogs or dogs with existing health problems.
Read more: Dog Not Eating and Smells Bad (Here’s why)
Key Takeaway
Bad breath in dogs is never something to ignore—especially when it’s paired with appetite loss.
Whether it’s dental disease, digestive issues, or something more serious like kidney or liver trouble, the combination of dog bad breath and not eating always deserves attention.
The good news? Many of the causes are treatable—especially when caught early.
Monitor your dog’s behavior closely, act quickly when something seems off, and don’t hesitate to reach out to your vet.
A little proactive care now can save your dog from pain and restore their health and comfort.